Apparatus for developing photographic recording materials

ABSTRACT

In developing apparatus for wet treatment of photographic recording materials, a trough in which a rotatable drum defining a support for the recording material is immersed in developer liquid is provided with two inlet orifices which are spaced apart so as to admit the desired liquid in two opposite flows at substantially uniform concentration and temperature of the developer liquid throughout the trough. The liquid is pumped to the second inlet orifice by a circulating pump, preferably mounted on the trough, through a branch pipe. The trough is preferably tippable and the branch pipe flexible. The trough may be longitudinally subdivided by a partition provided with a further inlet orifice.

United States Patent [1 1 Huss [451 Nov. 20, 1973 [54] APPARATUS FOR DEVELOPING PIIOTOGRAPI-IIC RECORDING MATERIALS [76] lnventor: Heinrich Huss, Liebigstrasse l,

605i Weiskirchen. Germany [22] Filed: Apr. 21, 1972 21 Appl. No.: 246,483

[30] Foreign Application Priority Data Apr. 24, 1971 Germany P 21 20 218.6

[52] US. Cl 95/96, 95/93, 220/22 [51] Int. Cl. G03d 3/02 [58] Field of Search 95/93, 95, 96, 97,

[56] References Cited UNITED STATES PATENTS 3,359,880 12/1967 Huss 95 93 2,469,825

5/ 1949 Hornstein 9/1961 Winnek 95/96 X 795,484 7/1905 Coble 220/22 X 1,580,476 4/1926 Fassio 95/97 UX 2,238,661 4/1941 Shaeffer 95/96 X Primary Examiner-Fred L. Braun Attorney-Karl F. Ross et al.

[5 7] ABSTRACT In developing apparatus for wet treatment of photographic recording materials, a trough in which a rotatable drum defining a support for the recording material is immersed in developer liquid is provided with two inlet orifices which are spaced apart so as to admit the desired liquid in two opposite flows at substantially uniform concentration and temperature of the developer liquid throughout the trough. The liquid is pumped to the second inlet orifice by a circulating pump, preferably mounted on the trough, through a branch pipe. The trough is preferably tippable and the branch pipe flexible. The trough may be longitudinally subdivided by a partition provided with a further inlet orifice.

5 Claims, 1 Drawing Figure APPARATUS FOR DEVELOPING PI-IOTOGRAPHIC RECORDING MATERIALS This invention relates to developing apparatus for wet treatment of photographic recording materials, the apparatus comprising an elongate trough for use in lightproof chamber, into which at least one rotatable drum defining a support for the recording material is at least partially immersed and into which are introduced via a supply conduit the developer liquids.

It is usual for the developer liquids to be admitted to the trough at one location whereby the trough gradually fills up, starting at the inlet location, while the drum with the material to be developed rotates in the trough. Particularly in the case of very long troughs, such as those required for one or more wide lengths of recording material, a certain amount of time is required for filling the trough, since there are limits to the inlet cross-section and fiow velocity. This results in those portions of the recording material on the drum which are closest to the supply orifice of the inlet conduit becoming immersed in the developer liquid earlier than the portions which are more remote therefrom. The resulting differential treatment times may, e.g., when developing color film, result in color distortion or achromatism. It is also possible, during or after the admission of the liquid, for regions of differential chemical composition or temperature to occur in the developer liquid and to lead to non-uniform results in the developing process.

It is therefore an object of the invention to provide a developing apparatus of the aforementioned kind in which the difficulties referred to are not present and in which the trough is rapidly and substantially uniformly charged with the developer liquid and the liquid throughout the developing process, is continuously maintained as a substantially uniform mixture and at a substantially uniform temperature.

I realize this object, in accordance with the present invention, by letting the supply conduit terminate at a first inlet orifice or port of the trough, preferably at an end wall thereof, and admitting part of the incoming liquid into the trough through a second inlet orifice or port remote from the first inlet port (e.g., in the opposite end wall) by way of another conduit branching off the supply conduit in the vicinity of the first inlet port. A pump in the branch conduit not only helps deliver fresh liquid to the second inlet port during filling but also serves, upon a halting of the influx of liquid by means of a shut-off valve in the supply conduit, to drive the liquid through the trough in a continuous flow entering at the second inlet port and exiting at the first inlet port. By virtue of this unidirectional circulation from the first-mentioned locationresults in a continuous of developer liquid through the trough, a continuous and substantially uniform mixing effect is achieved so that no regional differences of temperatures or chemical compositions are created.

By providing the inlet orifices in the two end walls, the trough is uniformly charged from two sides, and after charging a uniform current of liquid over the entire length of the trough takes place.

According to a further feature of the invention, the second inlet orifice may be located in a partition which is sealingly insertable in the trough. In this way the advantages referred to may also be achieved where the trough is subdivided into compartments for the purpose of using one compartment only for the developing process.

In a developing apparatus with a trough which is tippable for the purpose of emptying it, the circulating pump may be secured to the trough and tippable therewith; in that case it is connected to each of the inlet orifices by a flexible pipe Alternatively, the circulating pump may be mounted on a support structure tiltably supporting the trough therein, the branch conduit being constituted by flexible piping.

One form of developing apparatus embodying the in-, vention will now be described, by way of example, with reference to a somewhat simplified perspective view of such apparatus shown in the single FIGURE of the accompanying drawing.

A trough 1, into which a drum (not shown) supporting recording sheet material is immersed, has end walls 2, 3 provided with trunnions 4 about which it can be tipped for the purpose of emptying it. An apparatus of this description has been disclosed in my prior U.S. Pat. No. 3,359,880.

At one of the end walls 3 of the trough I an inlet orifice 5 of supply conduit 6 opens into the trough l in the vicinity of the trough floor, the trough being chargeable with the different developer liquids through the conduit 6. In the drawing the trough is shown as only partially filled with liquid.

A conduit 7 branches off the supply conduit 6 and leads to a circulating pump 8 whence another conduit 7 leads to a further inlet orifice 9 located in the vicinity of the trough floor at the other end wall 2.

In the course of the admission of the developer liquid to the trough 1, a part of the oncoming liquid from the supply conduit 6 is drawn off by pump 8 and delivered to the inlet orifice 9 opposite the inlet orifice 5, so that the trough is uniformly charged over its entire length on the counter-current principle. In the course of the developing process, circulatory pumping continues and a continuous longitudinal current of developer liquid flows in the trough 1 from the orifice 9 to the orifice 5, this current providing uniform distribution of concentration and temperature in the bath, even between the layers of the material being developed which moves in a direction perpendicular to the current.

As shown in the drawing, the circulating pump may be arranged outside the trough and connected thereto by flexible piping, so that the trough may be tipped (arrow A) to discharge the spent developer liquid; at that time the conduits 7, 7 and the pump 8 should be pumped empty before the next charge is admitted.

The pump may, for example, be in the form of a selfpriming pump and disposed above the liquid level in the trough. If in this arrangement the trough is tipped for the purpose of emptying it, the pump delivers all the remaining liquid still left in the conduits and in its own housing into the trough, whence it is discharged. It is, however, also possible to mount the pump on the trough; when the trough is tipped, the pump also runs dry. In this case the' pump need beself-priming only when it is located above the liquid level in the trough. A non-self-priming pump and its associated piping must be disposed at a lower lower than that of the trough floor and its housing must communicate with one of its associated pipes through a discharge conduit, so that it may empty itself duringtipping.

If the trough is subdivided by a partition shown chain-dotted in the drawing, I may confine the developing process to the region of the trough shown in the drawing to the left of the partition, ie. to the compartment adjacent the inlet port 5, in which case, the pipe 7' leading away from the pump 8 may be connected to an inlet orifice 9a in the partition 10, so that the same kind of rapid charging from two sides and thereafter a continuous longitudinal current during the developing process may be realized in the active compartment.

A stop valve 11 is shown provided in the supply conduit 6 in order to halt the influx of liquid after the trough has been charged.

The term developer liquids includes all liquids which may be admitted into the trough in the course of the developing process; this also includes water, which is required either merely for rinsing over a brief period or for the prolonged washing of the material to be developed.

I claim:

1. An apparatus for the developing of photographic sheet material, comprising:

a trough having first and second inlet ports, said trough being provided with support means for a drum carrying the sheet material to be developed;

a supply conduit with an entrance end for the developer liquid in communication with said first inlet P a branch conduit connected to said supply conduit at a location close to said first inlet port and in communication with said inlet port, said second inlet port being spaced from said first inlet port;

a pump in said branch conduit for promoting the delivery of part of a flow of incoming developer liquid from said supply conduit to said second inlet port during a filling operation; and

stop means in said supply conduit intermediate said entrance end and the junction of said branch conduit therewith for halting the flow of incoming liquid upon complete filling of the trough whereby the admitted liquid is unidirectionally circulated through said trough by said pump via said second inlet port, said first inlet port and said branch conduit.

2. An apparatus as defined in claim 1 wherein said trough is tiltably mounted and said pump is spaced from said trough, said branch conduit being flexible.

3. An apparatus as defined in claim 1 wherein said trough has a pair of opposite end walls, said first inlet port being disposed in one of said end walls.

4. An apparatus as defined in claim 3 wherein said second inlet port is disposed in the other of said end walls.

5. An apparatus as defined in claim 3 wherein said trough is provided with a partition between said end walls subdividing its interior into a first compartment proximal to said first inlet port and a second compartment remote from said first inlet port, said second inlet port being disposed in said partition. 

1. An apparatus for the developing of photographic sheet material, comprising: a trough having first and second inlet ports, said trough being provided with support means for a drum carrying the sheet material to be developed; a supply conduit with an entrance end for the developer liquid in communication with said first inlet port; a branch conduit connected to said supply conduit at a location close to said first inlet port and in communication with said inlet port, said second inlet port being spaced from said first inlet port; a pump in said branch conduit for promoting the delivery of part of a flow of incoming developer liquid from said supply conduit to said second inlet port during a filling operation; and stop means in said supply conduit intermediate said entrance end and the junction of said branch conduit therewith for halting the flow of incoming liquid upon complete filling of the trough whereby the admitted liquid is unidirectionally circulated through said trough by said pump via said second inlet port, said first inlet port and said branch conduit.
 2. An apparatus as defined in claim 1 wherein said trough is tiltably mounted and said pump is spaced from said trough, said branch conduit being flexible.
 3. An apparatus as defined in claim 1 wherein said trough has a pair of opposite end walls, said first inlet port being disposed in one of said end walls.
 4. An apparatus as defined in claim 3 wherein said second inlet port is disposed in the other of said end walls.
 5. An apparatus as defined in claim 3 wherein said trough is provided with a partition between said end walls subdividing its interior into a first compartment proximal to said first inlet port and a second compartment remote from said first inlet port, said second inlet port being disposed in said partition. 